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Query on if this is right - Loft Insulation


canalsiderenovation

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Ok, I don't know if this is right but we went up the bungalow loft with a view to putting the Xmas decorations up and it's looking pretty wet on the roof and is dripping a bit in that the insulation is a bit damp. Should it be like this? We have already got one very long snagging list gone to the builder already and I want to check if this is something else we should be mentioning or not so if I'm making a mountain out of a molehill please tell me! And no we don't have snow on our roof currently.

 

We still have bits of cladding needing to be sorted but that's on the pitched but with no loft and I don't want to create vents or gaps because we always seem to be a magnet for wasps and bluetits nesting. We already caught one trying to nest in not yet fitted hole to the utility extractor!

 

We had our EPC done a few weeks ago and they didn't make any suggestions on loft insulation.

 

There are in two different areas of the loft as you will recall we almost have two pitched roof areas and then the flat roof. The first pic is above our bedroom/dressing room which have in roof solar panels.

 

IMG_20210103_135724.thumb.jpg.ef16a92d388c0994cea0e548854a56cf.jpg

 

This sort is above a bathroom.

 

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IMG_20210103_135015.jpg

Edited by canalsiderenovation
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This is virtually the same post as I put on yesterday Showing condensation at my daughters loft

It definitely should be dry up there 

I’m on my way up there now 

There must be warm air getting into the loft 

 

This is ours that we built two years ago 

Just doing the same as most Getting rid of the x mas deco 

Freezing cold but dry 

image.jpg

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Heat from your house is getting into the loft by the sounds of it and the moisture is condensing on the cold roofing felt, the loft should have adequate ventilation (from outside) to remove any moisture that is there. I have come across loads of lofts where the insulation is sodden and the felt running with water. Definitely ask your builder why this is happening (then post that here so we can see if it’s BS ?‍♂️.)

Edited by joe90
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1 minute ago, joe90 said:

Heat from your house is getting into the loft by the sounds of it and the moisture is condensing on the cold roofing felt, the loft should have adequate ventilation (from outside) to remove any moisture that is there. I have come across loads of lofts where the insulation is sodden and the felt running with water. Definitely ask your builder why this is happening (then post that here so we can see if it’s BS ?‍♂️.

 

Thanks will do. There is quite a lot of things we have raised so at this rate he will need to be spending quite a bit of time back here!

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19 minutes ago, Mr Punter said:

Bear in mind it is abnormally cold outside and you have had a lot of building work that may have introduced a lot of water - bricklaying, plastering, decorating, screeding, concrete etc.

 

It's 4 degrees here and we have had no snow compared to other parts of the country. Infact we seem to have escaped the frosts and snowy weather others have had.

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39 minutes ago, canalsiderenovation said:

 

I guess this is something I need to add to our snagging list then!

This depends, it might be nothing to do with the builder. 

Who designed it, this should have been done at architectural stage and signed of by building regs. 

 

Your builder is not responsible for fixing everything that has been poorly designed 

you should have a vapour barrier at ceiling level, this should be in the design, and then the builder builds to that specification. 

If your spec is ceiling joists with 12.5mm plasterboard and skim, then I’m afraid that is rather under spec for a major refurbishment 

 

sorry but if your builder has installed the vents that are on your drawings then he has done what was asked, if there are vents missing then obviously he needs to rectify. 

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I believe these are the relevant parts and it does mention a vapour barrier but I don't know if we have this but I will raise it. 

 

Insulation ceiling level to be 150mm Rockwool insulation laid between ceiling joists with a further 170mm layer over joists (cross direction). 

 

Construct ceiling using 47x150mm sw joists at 400mm centres, finished internally with 12.5mm plasterboard and min 3mm thistle multi-finish plaster. Provide polythene vapour barrier between insulation and plasterboard. Provide opening at eaves level at least equal to continuous strip 25mm wide in two opposite sides to promote cross-ventilation.Mono pitched roofs to have ridge/high level ventilation equivalent to a 5mm gap via proprietary tile vents spaced in accordance with manufacturer’s details. 
 

 

 

Edited by canalsiderenovation
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7 minutes ago, canalsiderenovation said:

I believe these are the relevant parts and it does mention a vapour barrier but I don't know if we have this but I will raise it. 

 

Insulation ceiling level to be 150mm Rockwool insulation laid between ceiling joists with a further 170mm layer over joists (cross direction). 

 

Construct ceiling using 47x150mm sw joists at 400mm centres, finished internally with 12.5mm plasterboard and min 3mm thistle multi-finish plaster. Provide polythene vapour barrier between insulation and plasterboard. Provide opening at eaves level at least equal to continuous strip 25mm wide in two opposite sides to promote cross-ventilation.Mono pitched roofs to have ridge/high level ventilation equivalent to a 5mm gap via proprietary tile vents spaced in accordance with manufacturer’s details. 
 

 

 

Ok so that’s very clear, if it’s not there then. 

Im not sure really somebody has made  a big boo boo. 

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1 hour ago, Mr Punter said:

Bear in mind it is abnormally cold outside and you have had a lot of building work that may have introduced a lot of water - bricklaying, plastering, decorating, screeding, concrete etc.

Perfectly normal January winter weather.  Think yourself lucky you are not up here, -8 several nights and barely above 0 in the daytime for the last week.

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If up in the loft you should be able to push the insulation aside and see the vapour barrier atop the plasterboard. 

 

This is the concept the green membrane atop the plasterboard. 

 

SAM_0379

 

Viewed from up in the loft where there's no insulation you see the green vcl that's above the plasterboard.

 

Tbh I've punctured my vcl in so many places with speakers and lights etc I need to make good. 

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2 hours ago, Mr Punter said:

had a lot of building work that may have introduced a lot of water - bricklaying, plastering, decorating, screeding, concrete etc.

But this should be under the vapour barrier ?.

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2 minutes ago, joe90 said:

But this should be under the vapour barrier ?.

 

Should be but it is not a vapour barrier.  If it exists it is a vapour control layer at best.  Probably loft hatch, pipes, wires and ducts penetrating.  VCL is probably not contiguous with the outer leaf.

 

The roof needs low and high level ventilation.  Soffit and ridge.

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Ok so there is not a vapour barrier as this was not specified, only for the extension for the gym which we didn't end up having. The parts we have condensation are ultimately what was existing but we had the roof tiles, felt, ceilings etc replaced.

 

There is ridge ventilation and he is going to check all the insulation and look at putting in some fascias/soffit vents and is addressing this urgently.Screenshot_2021-01-04-13-19-14-084_com.google.android_apps.photos.thumb.jpg.ae248790fc24f5e9c3e2fb4fbb311848.jpgScreenshot_2021-01-04-13-19-03-287_com.google.android_apps.photos.thumb.jpg.8f8247bcde0259068b812553b0a43e1d.jpg

 

I did find some pics of work in progress.

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You need the low level as well.  It could be the over fascia type or soffit.  You should be able to feel cold air coming in.  Make sure the air path is not blocked by the insulation.  Having almost no wind does not help.  Try hanging out some wet washing in the current weather and you can see that evaporation does not happen quickly.

Edited by Mr Punter
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6 minutes ago, Mr Punter said:

You need the low level as well.  It could be the over fascia type or soffit.  You should be able to feel cold air coming in.  Make sure the air path is not blocked by the insulation.  Having almost no wind does not help.  Try hanging out some wet washing in the current weather and you can see that evaporation does not happen quickly.

 

Yes he is going to check all of this Thursday, Friday and Monday and is concerned so I'm sure it will be put right.

 

We have very little wind here as the old railway embankment keeps us very sheltered.

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What mr punter said. Ventilation. Where is it?

 

The vapour barrier is a red herring. My previous hgose was a 30's semi, just platerboard and 100mm rockwoll. Totally bone dry. Never an issue in 80 years. Why. Ventilation. On a windy day it was plenty draughty up there.

 

This looks like its sealed up.

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On 03/01/2021 at 16:10, canalsiderenovation said:

I believe these are the relevant parts and it does mention a vapour barrier but I don't know if we have this but I will raise it. 

 

Insulation ceiling level to be 150mm Rockwool insulation laid between ceiling joists with a further 170mm layer over joists (cross direction). 

 

Construct ceiling using 47x150mm sw joists at 400mm centres, finished internally with 12.5mm plasterboard and min 3mm thistle multi-finish plaster. Provide polythene vapour barrier between insulation and plasterboard. Provide opening at eaves level at least equal to continuous strip 25mm wide in two opposite sides to promote cross-ventilation.Mono pitched roofs to have ridge/high level ventilation equivalent to a 5mm gap via proprietary tile vents spaced in accordance with manufacturer’s details. 
 

 

 

If you move some of the insulation, can you see this vapour barrier? You should see if from the loft side.

 

EDIT: Sorry should have read all the way down first! lol.

 

You have a couple of options...

 

Increase airflow massively in the loft space to shift the moisture

Remove all the insulation, install a vapour barrier, and then replace insulation

Edited by MikeGrahamT21
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  • 2 weeks later...

So we raised this with the builder and some of these vent things were put in the fascias pretty much a couple of days after this post.

 

16108893075545964450594384384032.thumb.jpg.43a34a70b5e434e7841c75e4f7906de7.jpg

 

Not seen anyone since due to Covid and I've just been up the loft and it's pretty much the same as it was in the first pic with condensation, so around a week ago? Should these have had some impact by now?

 

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